{"product_id":"tempstar-40va-transformer-for-tne100j20g1-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for TNE100J20G1 — 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis genuine OEM 40VA control transformer (part number 1012722) supplies the low-voltage power for the Tempstar TNE100J20G1 furnace. It steps the 115-volt line input down to the 24-volt secondary that powers the control board, thermostat, gas valve, and relays. Rated at 40VA, it provides enough capacity for the furnace control circuit plus typical accessory loads. When this transformer fails — usually from a shorted secondary, overload, or age — the entire 24V control system goes dead: no thermostat display, no blower or burner response, and no ignition sequence. A buzzing, scorched, or open-winding transformer should be replaced immediately, and the cause of any short corrected before powering the new unit.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSpec\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003e1012722\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eStep-Down Control Transformer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eTempstar (ICP \/ Heil family)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRating\u003c\/td\u003e\n\u003ctd\u003e40 VA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Voltage\u003c\/td\u003e\n\u003ctd\u003e115 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Voltage\u003c\/td\u003e\n\u003ctd\u003e24 V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM direct replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDesigned for the Tempstar TNE100J20G1 and shared across ICP \/ Heil \/ Comfortmaker furnaces using a 115V-to-24V 40VA control transformer. Verify your primary line voltage is 115V and the VA rating matches before installing.\u003c\/p\u003e\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e — Disconnect power at the furnace switch and breaker and verify zero voltage with a multimeter on both line and load sides.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control\/electrical compartment service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph all primary and secondary leads and terminal connections before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and disconnect the primary (115V) and secondary (24V) wires, then remove the transformer mounting screws.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer, reconnect the line side to 115V and the load side to 24V exactly per your photo, and secure all terminals.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V at the secondary, a live thermostat, and normal blower\/ignition operation.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eNo 24V control power — dead thermostat and no furnace response\u003c\/li\u003e\n\u003cli\u003eLoud humming or buzzing from the transformer\u003c\/li\u003e\n\u003cli\u003eBurnt smell, scorched casing, or melted insulation\u003c\/li\u003e\n\u003cli\u003eOpen or shorted windings measured with a multimeter\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\u003cp\u003eShips same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021636944243,"sku":"1012722-GEN","price":32.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048413282675,"sku":"1012722","price":42.84,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1012722_a7a0ff0a-362e-4cf7-9a7e-2fdca0142e8c.jpg?v=1782958620","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-tne100j20g1-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}